GF09.40-P-4010P | Turbocharger, component description | 18.10.11 |
ENGINE 642 in MODEL 203.0 /2, 221.0 /1 up to Model Year 2008 /AEJ 07
ENGINE 642 up to 31.5.06 in MODEL 211.0 /2 /6, 219.3 up to 31.5.06
ENGINE 642 in MODEL 164.1 /8, 251.0 /1
except CODE (494) USA version
up to Model Year 2008 /AEJ 07
ENGINE 642 in MODEL 209.3 /4
ENGINE 642
in MODEL 461.3,
463.3 up to 31.5.12
P09.40-2173-09
110 Turbocharger
Location
The turbocharger sits at the rear between the two cylinder heads.
Task
The turbocharger has the task of pre-compressing the suctioned in air depending on the operating condition of the engine.
P09.40-2185-05
Design
1 Guide vanes "closed"
2 Guide vanes "opened"
a Turbine housing
b Turbine wheel
c Compressor housing
e Control rod pilot stud
f Adjusting ring
g Guide vane pilot stud
h Guide vane
A Compressor inlet (fresh air)
B Compressor outlet (pre-compressed air)
C Exhaust gases to turbine wheel
D Exhaust outlet
i1 Flow cross section with guide vanes "closed"
i2 Flow cross section with guide vanes "open"
Function
The exhaust gases of the engine are directed through the exhaust manifold into the turbine housing onto the turbine wheel. The flow energy of the exhaust gases sets the turbine wheel in rotation. As a result, the compressor wheel, which is connected to the turbine wheel by the turbine shaft, is also driven at the same speed. The fresh air inducted by the compressor wheel is compressed and passed to the engine. The boost pressure is regulated by adjusting the guide vanes which means changing the turbine geometry.
The pilot studs on the boost pressure positioner control rods (Y77/1) turn the adjusting ring in the turbine housing. As the pilot studs of the guide vanes also latch into the adjusting ring, all guide vanes are thus adjusted simultaneously.
At a lower engine speed the flow cross-section is downsized by closing the guide vanes. As a result, the flow rate of the exhaust gas at the turbine wheel is increased, which in turn increases the speed of the exhaust turbocharger and thus boosts the boost pressure.
At higher engine speeds, the guide vanes are opened increasingly and thus the flow cross-section increased. As a result, the flow rate of the exhaust gas at the turbine wheel is decreased, which in turn decreases the speed of the exhaust turbocharger and thus lowers the boost pressure.
Adjustment of the turbine geometry of the turbocharger takes place via the boost pressure positioner.